The present invention relates in general to a marker for identifying an object in a system which includes a source of irradiance and a detector of light emitted from the marker. More particularly, the present invention relates to a removable data storage cartridge and to a data storage drive for receiving the cartridge. Even more particularly, the present invention relates to detecting the presence of the correct disk cartridge in the data storage drive by use of a latent illuminance tag on the cartridge.
Disk drives for receiving removable disk cartridges, including conventional 3.5 inch floppy disk drives, must have some mechanism for detecting the insertion or presence of a disk cartridge in the drive. The actuator that carries the recording heads of the disk drive across the recording surfaces of the disk should not be allowed to move unless the presence of an appropriate disk cartridge which is non-drive damaging is detected. The removability feature requires that the disk drive have a cartridge insertion opening into which foreign objects can be inserted. If these objects physically engage the drive as a legitimate cartridge would, then the heads could be loaded onto or into the foreign object, thereby destroying the drive. Also, the spindle motor of the disk drive will be activated by a falsely detected foreign object, thereby generating particle debris. In the prior art, mechanical switches are typically employed to detect the presence of a disk cartridge within the drive. Such switches are typically positioned such that when a disk cartridge is inserted fully into the drive, the cartridge contacts the switch, thereby providing an indication that the disk cartridge is present. xe2x80x9cRETROREFLECTIVE MARKER FOR DATA STORAGE CARTRIDGExe2x80x9d, U.S. Pat. No. 5,638,228, to Thomas, III, describes the reflection of a highly concentrated quasi circular lobe of light whose spread on reflection is captured by the aperture of a phototransistor in close proximity to a light emitting diode (LED). This emitter/detector pair is in the drive and a retroreflective array is on the cartridge. The desired light lobe size is provided by the geometric size of the retroreflector array elements relative to the spacing of the emitter and the detector in the drive. Due to this physical size matching and the fact that retroreflectors are used, this marker on the cartridge is quite insensitive to cartridge tilt and distance from the emitter/detector pair in the drive. This patent is incorporated herein by reference.
Recently, very small mini-cartridges have been developed for use in miniature disc drives. These mini-drives are incorporated into hand-held devices such as digital cameras, electronic books, global positioning systems, cellular phones and the like. xe2x80x9cINTERCHANGEABLE CARTRIDGE DATA STORAGE SYSTEM FOR DEVICES PERFORMING DIVERSE FUNCTIONSxe2x80x9d, Ser. No. 08/746,085, filed Nov. 6, 1996, Edwards, et al. (Attorney""s Docket IOM-9319) describes such mini-cartridges, mini-drives, and hand-held devices. This application is incorporated herein by reference.
As disk storage products become smaller and smaller, the need for a cartridge marker of thinner physical size is required. In very thin disk drives where the distance between the cartridge tag and the optical sensing device is very small (e.g., 1 mm), the inherent reflective gain mechanism obtained with a retroreflector over a diffuse or specular reflector is lost. Holographic directional light control is possible, but due to the very small working distances the ability for false engagement of the drive is significantly increased with that approach.
The ability to discriminate between cartridge types after insertion into a data storage device but prior to putting the read/write heads on the recording media is of significant value and utility. Principally this utility comes from the ability to detect the difference between various capacities or generations of data storage cartridges in a downward media compatible data storage drive. This discrimination capability allows for drive/media specific adjustments to be made such as media rotation rate, data channel rates, location of Z track for initial seeking, or even mechanical adjustment in the drive like the active engagement of new crash stop locations. The ability of a disk drive to predetermine the type/generation of data storage cartridge inserted into it prior to enabling the spin-up and engagement of read/write elements also provides the drive system designer with new possibilities for cross-platform interchangeability.
A xe2x80x9ccaddyxe2x80x9d cartridge, as mentioned in the aforementioned Edwards, et al. application provides cross drive platform compatibility, for example between mini-cartridges and personal computer cartridges. The ability to recognize the installation of a xe2x80x9ccaddyxe2x80x9d into the drive prior to spinning up of the xe2x80x9ccaddyxe2x80x9d and loading of heads is necessary. Again rotational speed adjustments, Z track location information, data channel rate and crash stop/ID and OD data track location information must be determined prior to read/write head loading. This invention provides a solution of these problems also.
Another problem associated with the detection of LED light reflected from any reflective material is the occurrence of illuminance hot spots or structure in the LED output which often results in uneven illumination of the cartridge marker. Reflective cartridge markers can also become faded, scratched, or soiled. These factors combine to make the amplitude of the detected light signal highly variable.
Recently, in various industries such as the distribution industry, phosphors have been used in the control of goods by means of bar codes, and furthermore, bar codes are printed on various prepaid cards and passing cards, and these bar codes are read by optical reading apparatuses such as scanners to perform the desired actions. Moreover, various attempts have been made to apply forgery preventive means to credit cards and prepaid cards or to detect forged cards. For example, the marks such as bar codes are printed with an ink containing a phosphor by offset printing or by using an ink ribbon to form latent image marks. The latent image marks are irradiated with a semiconductor laser beam to excite the phosphor and the light emitted from the phosphor is received to read the bar code information by an optical reading apparatus. These techniques use the content or spectral shift from the irradiating light source for identification.
Although the art of detecting and discriminating between data storage cartridges is well developed, there remain some problems inherent in this technology, particularly when the distance between the cartridge tag and the optical sensing device is between about 1 mm and about 15 mm. Therefore, a need exists for a tag that produces reliable detection and discrimination between data storage cartridges under varying gain and marker spacings.
The present invention is directed to a data storage drive comprising a source of irradiance; a detector of irradiance; and means for enabling the drive. The detector is connected to enable the means for enabling the drive when the detected irradiance indicates a predetermined decay time. The source of irradiance is preferably a light emitting diode (LED), and more preferably, a flood LED. The detector is preferably a phototransistor or a photodiode.
According to one aspect of the present invention, the drive further comprises monitoring means for monitoring the output of the detector and determining a decay time of the detected irradiance. The detector is connected to enable the drive when the decay time substantially equals the predetermined decay time. Preferably, the monitoring means comprises a microprocessor.
According to another aspect of the present invention, the drive further comprises a filter for filtering at least one predetermined wavelength from entering the detector.
In a further embodiment within the scope of the present invention, the data storage drive is adapted to receive a cartridge comprising a body; a data storage medium in the body; and a marker on the body. The marker is a latent illuminance material which receives irradiance from the source and emits irradiance toward the detector for detection, and the detector is connected to enable the means for enabling the drive when the detected irradiance indicates a predetermined decay time.
According to a further aspect of the present invention, the drive further comprises a plurality of sources of irradiance to emit irradiance at a first plurality of wavelengths; and a plurality of detectors of irradiance to detect irradiance at a second plurality of wavelengths, whereby detection of particular ones of the second plurality of wavelengths identifies a type of cartridge.
According to further aspects of the present invention, ratiometric measurements on the second plurality of wavelengths identify a type of cartridge. The marker has a latent illuminance wavelength spectrum in the range between about 450 nm and about 1050 nm, and preferably has a latent illuminance wavelength spectrum in the range between about 680 nm and about 800 nm.
According to further aspects of the present invention, the irradiance wavelength is outside of the latent illuminance wavelength spectrum, and the latent illuminance material comprises a phosphorescent material. Preferably, the phosphorescent material comprises a rare earth phosphor, which is a Stokes phosphor or an anti-Stokes phosphor.
According to further aspects of the present invention, the latent illuminance material has a decay time which is used to identify the cartridge. Preferably, the decay time is in the range between about 50 xcexcsec and about 3,000 xcexcsec. The decay time is an amount of time for the irradiance emitted from the marker to decay to a predetermined intensity value. According to one aspect, the decay time is an amount of time for the irradiance emitted from the marker to decay from a first intensity value to a second intensity value.
The irradiance emitted from the marker has an intensity that decays exponentially or as the sum of a plurality of differently weighted exponential decays. Preferably, the intensity of the irradiance decays according to exe2x88x92(t/(T/X)), where T is a decay time constant for a predetermined amount of decay, X is a predetermined constant, and t is a time that has elapsed from when the source of irradiance stops providing the irradiance.
According to further aspects of the present invention, the latent illuminance material is coated on a pressure sensitive sticker substrate, is suspended in one of an adhesive compound and a glue, is blended with an ink and printed on the body, or is injection molded on the body.
According to one aspect of the present invention, the marker further comprises a filter to absorb light having a predetermined range of wavelengths. The filter comprises a thin film coating spectral absorption layer and/or the filter comprises a rare earth element. Preferably, the rare earth element is ytterbium.
Another embodiment within the scope of this invention includes a combination of a data storage drive and a cartridge for the drive. The drive comprises a source of irradiance at an irradiance wavelength; a detector of irradiance; and means for enabling the drive. The cartridge comprises a body; a data storage medium in the body; and a marker on the body. The marker is a latent illuminance material which receives irradiance from the source and emits irradiance having a spectral characteristic toward the detector for detection, and the detector is connected to enable the means for enabling the drive when the detected spectral characteristic indicates a predetermined characteristic.
Another embodiment within the scope of this invention is directed to a combination of a data storage drive and a cartridge for the drive. The drive comprises a source of irradiance at an irradiance wavelength; a detector of irradiance; and means for enabling the drive. The cartridge comprises a body; a data storage medium in the body; and means for providing irradiance having a decay time toward the detector for detection. The detector is connected to enable the means for enabling the drive when the decay time of the detected irradiance substantially equals a predetermined decay time.
Preferably, the means for providing irradiance comprises means for detecting the irradiance from the source of irradiance; and means for emitting decaying irradiance toward the detector for detection when the irradiance is detected from the source of irradiance by the means for detecting. The means for detecting the irradiance from the source of irradiance comprises a photodetector on the body for detecting the irradiance from the source of irradiance, and the means for emitting decaying irradiance comprises a light source on the body and electrically connected to the photodetector.
According to further aspects of the present invention, the light source is an LED, the photodetector and the light source are disposed on an integrated circuit, and the integrated circuit is powered by a battery or the source of irradiance.
The foregoing and other aspects of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.